This study aims to examine the relationship between family control and earnings quality, while simultaneously investigating the moderating effect of environmental, social and governance (ESG) reporting on this relationship. The sample comprises companies listed on the Stock Exchange of Thailand during 2019 to 2023. The measure of degree of earnings quality is proxies by accrual-based earnings management. The multiple regression analysis and two-stage least-squares (2SLS) regression was utilized. The result from hypothesis testing found that family control firms would demonstrate lower earnings quality. In addition, it was found that an increase in degree of ESG Reporting significantly moderates the relationship between family control and earnings quality in a positively manner. This result supports the agency theory which explains that highly family-controlled lead to higher agency costs which would consequently lead to reduced earnings quality. Furthermore, this empirical study provides the Securities and Exchange Commission and the Federation of Accounting Professions with important information to consider when developing regulations and guideline for the environmental, social and governance (ESG) reporting for firms.